A sorter is a device able to sort items according to their identification and by loading or inducting the items onto the sorter and unloading, i.e. discharging them, at a discharge in accordance with the identification and thus into one or more discharges dedicated the items.
Sorters of the type as the present invention are typically suited for sorting several thousands of items per hour. Thus, e.g. a substantial amount of energy may be used by the system and some acoustic noise may also be generated. Furthermore, due to a need for high performance, e.g. in terms of number of sorted items per hour, but also including a need for extreme reliability, each part of the system must be engineered to suit these needs.
Line sorters are known, where a closed loop of coupled sorting carts or slats for carrying items to be sorted move on a track loop, e.g. with wheels. In case of long line sorters, e.g. lengths of 10-100 m, it is a problem that the length of the closed loop of carts or slats will vary, e.g. according to temperature (summer/winter) and due to wear in the couplings. Such mismatch between length of the track loop and the closed loop of coupled carts or slats will introduce extra acoustic noise and vibrations during operation, and it may cause extra wear on both tracks and couplings, and it may even cause breakdown. This problem can be solved by introducing a length adjustment mechanism on some of or all of the carts or slats in the closed loop. However, such adjustment mechanism adds extra costs to the sorter system, and the adjustment mechanism in itself introduces a potential source of error. Further, a manually operated length adjustment on individual carts or slats involves a complicated procedure which requires that the sorter is stopped, and thus it is required that the sorter is out of operation for a period of time.